A conventional tool cabinet includes a cabinet body and a plurality of drawers that are vertically stacked one above the other in the cabinet body. The conventional tool cabinet is used f or storing and systematizing items stored in the drawers, such as files, hand tools, power tools, and so on, in a ready-to-use manner. The top wall of the cabinet body also serves as a working table far a user to work thereon with the tools taken out from the drawers. However, since the height of the top wall is unadjustable, the conventional tool cabinet is not suitable for users of different heights to work on the top wall thereof, thereby resulting in possible inconvenience during use. Moreover, since the top wall of the cabinet body also serves as an extra storage spot for some items to be placed thereon while the top wall is not used as a working table, storage space of the conventional tool cabinet say be scarce when the top wall is in use.